X Is Boring–Claudius Gave us the Anti-Sigma!

Suetonius, Divius Claudius 41-42

“[The emperor Claudius] wrote an eight-volume autobiography, rather gauche in character instead of poorly written. He also wrote a defense of Cicero against Asinius Gallus, a book of sufficient erudition. In addition to this, he added three new letters to the old alphabet because he believed they were really needed. He wrote about about this when he was still a private citizen. Once he was princeps, he found it was no challenge to encourage their common use. Many of examples of theses can still be scene in books, in annals of the time, and on public works.

Well, he also pursued Greek studies with no minor zeal, confessing his love for the language and its superiority at every opportunity.”

Composuit et de vita sua octo volumina, magis inepte quam ineleganter; item Ciceronis defensionem adversus Asini Galli libros satis eruditam. Novas etiam commentus est litteras tres ac numero veterum quasi maxime necessarias addidit; de quarum ratione cum privatus adhuc volumen edidisset, mox princeps non difficulter optinuit ut in usu quoque promiscuo essent. Exstat talis scriptura in plerisque libris ac diurnis titulisque operum.Nec minore cura Graeca studia secutus est, amorem praestantiamque linguae occasione omni professus.

Ↄ or ↃϹ/X (antisigma) to replace BS and PS, much as X stood in for CS and GS.
Ⅎ, a turned F or digamma (digamma inversum) to be used instead of the letter V when denoting the consonantal u
Ⱶ, a half H. The value of this letter is unclear, but perhaps it represented the so-called sonus medius, a short vowel sound (likely /ɨ/ or /ʉ/). to represent the sound value between u and i .